Today, a variety of different bookbinding systems can deliver professionally bound documents, including books, manuals, publications, annual reports, newsletters, business plans, and brochures. A bookbinding system generally may be classified as a commercial (or trade) bookbinding system that is designed for in-line manufacturing of high quality volume runs or an in-house (or office) bookbinding system designed for short “on-demand” runs. Commercial bookbinding systems generally provide a wide variety of binding capabilities, but require large production runs (e.g., on the order of thousands of bindings) to offset the set-up cost of each production run and to support the necessary investment in expensive in-line production equipment. Office bookbinding systems, on the other hand, generally involve manual intervention and provide relatively few binding capabilities, but are significantly less expensive to set up and operate than commercial bookbinding systems, even for short on-demand production runs of only a few books.
In general, a bookbinding system collects a plurality of sheets (or pages) into a text body (or book block) that includes a spine and two side hinge areas. The bookbinding system applies an adhesive to the text body spine to bind the sheets together. A cover may be attached to the bound text body by applying an adhesive to the side hinge areas or the spine of the text body, or both. The cover of a typical commercial soft cover book generally is attached to the text body spine. The covers of hardcover books and some soft cover “lay flat” books, on the other hand, typically are attached to the side hinge areas of the text body and are not attached to the text body spines (i.e., the spines are “floating”).
Many different systems have been proposed for applying adhesive to a text body spine to bind the text body sheets together.
For example, U.S. Pat. No. 6,024,525 describes a bookbinder that includes a tape heating apparatus with a main heater and a pair of side heaters. The main heater is configured to preheat the entire length of a hot melt adhesive tape. After the spine of a text body is pressed against the preheated hot melt adhesive tape, the pair of side heaters press the overhanging sides of the adhesive tape against the text body to complete the binding of the sheets into a bound text body.
U.S. Pat. No. 5,346,350 discloses an apparatus for binding sheets that includes an aligning plate that aligns the sheets at the spine edge, and two clamping plates that hold the sheets during binding. A heating platen heats and melts a backless solid hot melt adhesive that is placed along the sheet edges. The hot melt adhesive binds the sheets together at the spinal area. According to the '350 patent:                Capillary action is the preferred primary mechanism by which the adhesive flows into the stack 12 to bond the paper sheets together. Capillary action assists both the adhesion of the adhesive material 94 to the stack of paper 12 and the internal cohesion within the adhesive material 94. . . .        Additionally, the platen 120 of the heating subsystem 118 does not push the adhesive 94 into the edge 13 of the stack 12. Ideally, the platen 120 applies zero pressure against the stack 12 and only contacts the adhesive material sheet 94 sufficiently to melt the adhesive 94 so that the gravity-assisted capillary action causes the liquid adhesive 94 to wick into and bond the stack 12 together. Putting pressure on the adhesive 94 in an attempt to push it into the stack 12, whether pushing downwardly, upwardly, or sideways, would not enhance bonding. Rather, this would squeeze the adhesive off of the edge 13 and off of the stack 12 through the sides between the platen 120 and the stack 12 and defeat the effects of capillary action. Thus, the platen is designed to apply only minimal pressures on the edge 13 of the stack 12 to maintain contact between the platen 120, the adhesive 94 and the stack 12.        (Col. 8, line 60 through col. 9, line 29)The hot melt adhesive also may be used to attach a preformed book cover to the text body spine.        
International Patent Publication No. WO 99/38707 discloses a paperback bookbinding scheme in which a cover with an adhesive strip disposed along a spine area is forced between a pair of pressing rollers to form a pocket, and a text body is inserted into the pocket with the text body spine in contact with the adhesive strip. The pressing rollers move forcibly toward one another to compress the cover firmly against the front and back sides of the text body and to compress the text body sheets together tightly in the area adjacent to the spine. A sonic tool transmits sonic energy to the cover to activate the adhesive strip and, thereby, bind the text body sheets and the cover into a perfectly bound book.
U.S. Pat. No. 4,911,475 discloses a bookbinding construction in which sheets are bound together into a book block by two or more spaced-apart transverse segments of adhesive. The front section of a cover is attached to the first page of the book block and the back section of the cover is secured to the last page of the book block. Upon opening the book or turning a page, glue-free portions of the spine edge of the open page flex or bow outward over the facing page in a wedging manner or interfering fit. According to the '475 patent, this wedging action against the opposite page resists the tendency of the book to spring closed and forces the pages of the book to lie flat.
U.S. Pat. No. 5,271,794 discloses an adhesive applicator that is configured to spread coat an adhesive onto the spine and side edges of a text body to bind the text body sheets and a cover into a perfectly bound book with an attached spine. The adhesive applicator includes a book spine coating nozzle with adjustable side sealing jaws for adjusting the nozzle width for different book thicknesses and separate side glue outlets for depositing glue on the book sides. Glue flow control valves are disposed between the spine coating nozzle and the side glue outlets so the glue deposited on the book sides may be selectively and independently cut off or controlled.
Still other bookbinding systems have been proposed.